Gender equity issues remain a challenge in science, technology, engineering, and mathematics (STEM) fields, where women are highly underrepresented. As integrated STEM instruction becomes increasingly popular in elementary and middle school classrooms, it is important to consider whether the small group activities that are commonplace in STEM instruction support the equitable participation of young girls. This study builds on the existing body of literature to better understand how gender is related to student participation in small group STEM activities and whether students participate differently in science and engineering activities. A single embedded case study was used to explore the experiences of four students aged 10-11 years as they participated in small group work within an integrated STEM unit in their fifth-grade classroom. Two girls and two boys worked together throughout the unit to explore science content related to electromagnetism and apply their content knowledge to an engineering design challenge. Video and audio of students' small group interactions were analyzed using an observation protocol to code their participation in each 3-min segment of STEM activity. Student- and case-level analyses were used to identify patterns of interaction based on gender and type of activity (science vs. engineering). Findings suggest that boys and girls participate in small group STEM activities in different ways, adopting distinct roles within their group. In addition, students displayed divergent patterns of interaction in science- and engineering-focused lessons, suggesting that students need additional practice and support in navigating between science and engineering in integrated STEM units.